An optical proximity sensor is a sensor able to detect the presence of nearby objects by means of electromagnetic radiation without any physical contact. Typically, a proximity sensor emits a continuous or pulsed electromagnetic field, e.g. infrared, and detects changes in the field or return signal. The term “optical” in this respect relates to the infrared, visible and ultraviolet part of the electromagnetic spectrum.
Currently, typical optical proximity sensors are realized with multi-chip packages based on printed circuit boards (PCB) which are over-molded by common molding techniques. These packages, however, are bulky and have rather big footprint. On the other side optical proximity sensors find increased application in modern mobile devices like smartphones, personal digital assistants (PDA), laptops and the like. With such devices there is a strong need to reduce size and increase functionality per area.